The goal of this K02 proposal is to allow the applicant to devote 75% of his time during the next five years to exploring the structural basis of dilated cardiomyopathy. In particular, the PI will focus on the elucidation of the functional interactions between phospholamban (PLB) and sarco(endo) plasmic Ca-ATPase (SERCA), and PLB and protein Kinase A (PKA). The functional interactions of PLB with both SERCA and PKA are pivotal for maintaining calcium homeostasis in muscle, and their characterization may lead to novel therapeutic strategies including the introduction of new drugs and improve gene therapy. Time-off from teaching and service would allow the applicant to develop new strategies for the elucidation of these protein-protein interactions and to travel to the NIH-funded National High Magnetic Field Laboratory in Florida. New approaches are needed because the complexes to be characterized involve membrane proteins, which have proven notoriously recalcitrant to the classical methods of structural biology. The PI group has obtained new and promising results towards the characterization of these protein-protein interactions, but new spectroscopic techniques are needed to refine these results. These techniques will include 1) new solution NMR approaches using detergent micelles to study functional complexes, 2) new solid-state NMR approaches to study the mechanically oriented complexes, and 3) solid-state NMR Magic Angle Spinning techniques to study membrane protein complexes in synthetic lipid bilayers. The latter two techniques will be developed at the National High Magnetic Field Laboratory. Since protein-protein complexes between membrane proteins play a central role in signal transduction mechanisms, the new technologies developed by the applicant upon completion of the K02 award are expected to not only characterize protein complexes involved in calcium regulation in muscle, but to be applicable to the cellular processes of homologous systems as well.